Micro-additions to tin alloys

Abstract

Tin-based alloys that include micro-additions of certain elements avoid the discoloration that otherwise afflict those alloys when they are melted. The discoloration, which results from tin oxidation, correlates with poor performance of the alloys in filler metal applications. A preferred method of preparing the alloys of the invention is by rapid solidification from the melt.

We claim: 
     
       1. A tin-based alloy consisting essentially of silver, antimony, tin, and at least one element selected from the group consisting of zinc, phosphorus, aluminum, magnesium, gallium and calcium, the total concentration in the alloy of elements of said group being between about 3 and about 100 parts per million, by weight, and sufficient to inhibit substantially oxidation of tin during melting of the alloy. 
     
     
       2. The alloy of claim 1 in which silver is about 25 weight percent and antimony is about 10 weight percent. 
     
     
       3. The alloy of claim 1 in which the amounts, in ppm, of Zn, P, Al, Mg, Ga, and Ca, are denoted by p, q, r, s, t, and u, respectively, and p/4+r/5+s/11+t/12+u/28 equals at least about 1.